Pedestrian counting is required in diversified places such as shopping malls, touristic spots, etc., however, a low-cost solution to this problem is yet to be proposed in the literature. Therefore, in this paper, we propose a new solution for pedestrian counting that exploits only a small number of COTS sensors (94% less than that used in the existing Eco-Counter solution). To do so, we propose detail designs and two different algorithms for separately sensing step-down and step-up phenomena that we find while walking. User evaluation of real implementations of both our algorithms confirms an average accuracy of up to 93% through sensing the step-up phenomena.

1. Sparse Mat: A Tale of Devising A Low-Cost
Directional System for Pedestrian Counting
Department of Computer Science and Engineering,
Bangladesh University of Engineering and Technology, Dhaka, Bangladesh
NSysS 2017
Dhaka, Bangladesh
Tarik Reza Toha, Salman Estyak, Taslim Arefin Khan,
Tusher Chakraborty, and A. B. M. Alim Al Islam

2. Outline
• Background and motivation
• Our proposed system
– Design
– Implementation
– Experimentation
• User evaluation
• Conclusion and future work
2

3. Background: Pedestrian Counting
3

4. Applications of Pedestrian Counting
• Strategic business
research
– Tourist flow estimation
• Security and emergency
support
– Victim count estimation
for rescue operations
• Optimization tasks
– Railway stations,
shopping malls, airports,
hospitals, etc.
4
Assign staff deployment to demand

5. Classical Pedestrian Counting Technique
5
• Low human mobility
– Using pen and paper,
or tally counter
• High human mobility
– Automated pedestrian counter is
required

6. Existing Automated Counting Techniques
6
Pros:
 High accuracy
Cons:
 High cost
 High power
Pros:
 Low-cost
 Low-power
 Easy setup process
Cons:
 Low accuracy
Laser scanner counter
[Katabira et al., ACRS, 2004]
Infrared beam counter
[Wienand et al., USPTO, 2001]
Cons:
 High cost
 Complex algorithms
 High processing power
Pros:
 High accuracy
Camera-based counter
[Agusta et al., ICCEMS, 2014]
Existing high-end device
based solutions are high-cost
and high-power

7. Existing Mat-Based Counting Technologies
7
Greneker et al., 1996
(2000 sensors/sq. ft.)
Kutschera et al., 2011
(90 sensors/sq. ft.)
Instant Counting Mat by Milon et al., 2013
(56 sensors/sq. ft.)
Existing mat-based solutions
demand high densities of
expensive sensors

8. Our Contribution
8
We propose a mat-based pedestrian counting solution
comprising low density (~3 sensors/sq. ft.) of low-cost
sensors, which exhibits a high accuracy in pedestrian
counting
Sparse Mat

9. Underlying Sensing Mechanism
9

10. Sparse Mat: Operational Block Diagram
10
Block diagram
Cross sectional view of
sensing module

11. Snapshot of Sparse Mat
11
Sensing Module
Controller
Module

12. Piezoelectric Sensor Responses for Varying
Radial Distances
12
Piezoelectric sensor responses under varying points of
pressure over the hardboard block
Coverage of piezoelectric sensor response
Vibration propagation while knocking
on a hardboard block, which covered a
piezoelectric sensor

13. Sensing Step-Down Phenomena
13
Sensor placement over mat Sensor placement along with
taped foam
Hardboard block placement
over sensors

14. Findings from 2×2 Piezo-grid
14
Piezoelectric sensor responses while
moving towards from down row to up row
over the left sensors
Piezoelectric sensor responses while
moving towards from up row to down row
over the right sensors
drdl
ul ur
drdl
ul ur
The varying response time
can significantly undermine
the accuracy of directional
pedestrian counting

15. Resilience to Variation in Response Time:
2×3 Piezo-grid?
15
Sensor placement over mat Sensor placement along with
taped foam
Hardboard block placement
over sensors

16. Findings from 2×3 Piezo-grid
16
Piezoelectric sensor responses while
moving towards from down row to up
row
Piezoelectric sensor responses while
moving towards from up row to down
row
drdl
ul ur
dm
um
drdl
ul ur
dm
um
The ending always maintains
perfect order even though
starting may not!

17. Sensing Step-up Phenomena
17

18. Modified Settings in 2×3 Piezo-grid
18
Sensor placement over mat Sensor placement along with
taped foam
Hardboard block placement
over sensors

19. Enhancing Sensing Accuracy: 3×2 Piezo-grid
19
Sensor placement over mat Sensor placement along with
taped foam
Hardboard block placement
over sensors

20. User Evaluation of Preliminary Designs
Grid Sensing Phenomena Accuracy (%) Causes
2×2 Step-Down < 50
Response time varies significantly from
sensor to sensor
2×3 Step-Down 60
Time delay between placing heel and toe
is very small
2×3 Step-Up 75
Participants often failed to place their
foot step over both hardboard blocks
20

21. User Evaluation of the Final Design:
3×2 Piezo-grid Sensing Step-Up
Age
Height
(inch)
Weight
(kg)
Shoe length
(inch)
Total attempts
Successful
detection
Device
accuracy (%)
22 66 68 11 18 14 78
22 70 62 11.25 20 20 100
22 73 81 12 10 8 80
23 70 90 11.25 20 20 100
25 68 72 11.25 20 20 100
26 66 55 11 8 7 88
Total 96 89 93
21

22. Conclusion and Future Work
• Existing automated directional pedestrian counters are generally
highly expensive
• We propose a low-cost and easily-to-deploy automated directional
pedestrian counter without compromising accuracy
– Uses sparser sensors than any other state-of-the-art technologies
 94% sparser than Instant Counting Mat
– User evaluation of real implementations confirms an average accuracy of
93%
• Future work
– Workable for different types of users such as kids
– Determine multiple footsteps of a single person
– Determine multiple persons traversing in parallel over the sensor mat
22

23. A Short Demonstration of Sparse Mat
23
• https://youtu.be/C7MB58Xvr_w

24. Thank you
Questions are welcome!
Email: tarik.toha@gmail.com
24

25. Variable Sensor Response Times
25

26. Towards Sensing Step-up Phenomena (contd.)
26
Flowchart of step-down phenomena
sensing algorithm
Flowchart of step-up phenomena sensing
algorithm